Clamping device for explosion panels

ABSTRACT

A clamping device for stiff explosion panels for closing off a safety opening in a holder filled with powder, gas or vapor, where a frame is fastened around the safety opening and several inclined clip strips are provided between the frame and the sides of the explosion panel for pressing the explosion panel onto the frame, wherein the clamping device comprises plural upright connecting blocks, a housing for each connecting block which fits over the associated connecting block to cover the connecting block, two clamping edges in each housing lying opposite one another, the connecting blocks and housings being spaced apart, one of each of the connecting blocks and associated housing being fastened to the perimeter of the explosion panel and the other to the perimeter of the frame, and at least two diverging clip strips in each housing, one end of each strip being supported by the connecting block and the other end pressing on one of the clamping edges of the housing in order to connect the housing to the connecting block, and, in turn, the explosion panel to the holder.

The invention is for a clamping device for retaining an explosion panelon the safety opening of holders in which there is a powder, gas orvapour, which explosion panel in the event of excess pressure, forexample resulting from an explosion in the holder, is thrown open orblown away, so that the holder sustains little or no damage.

European patent application EP-A-O 351 457 of applicant describes aclamping device of this sort in which use is made of a stiff explosionpanel in stainless steel which is provided all around with a side with aclamping edge which is folded inwards, on which grip the free ends ofseveral inclined clip strips which are directed towards said clampingstrip and which are attached to a frame provided around the safetyopening of the holder and thus press the explosion panel firmly to theframe.

When an explosion occurs in the holder, the explosion panel is raised bythe generated pressure and the stiff clamping edge of the explosionpanel bends the free ends of the clip strips upwards, causing theexplosion panel to slide freely over the clip strips and be blown awayfrom the safety opening.

A disadvantage of such an explosion panel with clamping edges is thatthe stainless steel from which the panel is made is an expensivematerial and that moreover the production of such a panel which must bepressed into a certain form in order to give it adequate stiffness isexpensive. Another disadvantage is that dirt can easily lodge betweenthe clip strips and the clamping edge of the panel, so that it is moredifficult for the clip strips to react and only when the pressure on theexplosion panel is greater than intended. Another disadvantage is thatwhen the opening pressure of the explosion panel is high, the inclinedclip strips must hold the clamping edge of the panel firmly against theedge of the safety opening, so that for blowing away the panel, theadditional friction which arises during the raising of the panel betweenthe panel and the frame provided around the safety opening, must beovercome. The opening pressure required for this is consequentlydifficult to predict.

From the U.S. Pat. No. 4,308,695 a pressure-relieving facade structurefor a building is known. This structure has a plurality of slab-likeelements, a plurality of retaining legs each extending from one of theslab-like elements toward the facade of the building and having athickened clamping projection at its free end, and a plurality ofelastic receiving elements attached to the facade of the building andreleasably receiving the clamping projections of the retaining legs withelastic clamping action.

Also, this structure has the disadvantage that dirt can easily lodgebetween the different elements of the structure. Besides the elasticelements have the disadvantage that they are unsuitable for holding anexplosion panel on the safety opening of a holder, because of the shapeand the material of the elastic elements.

In order to remedy these disadvantages a clamping device has, pursuantto the chief characteristic of the invention, been realized whichconsists of several upright connecting blocks, for each connecting blocka housing which fits over same for protecting the connecting block, ineach housing two clamping edges which lie opposite one another, whichclamping blocks and housings are mounted at a distance from one another,one of the two to the perimeter of the explosion panel and the others tothe perimeter of the frame, and in each housing at least two divergingclip strips one end of which is mounted on the connecting block whilethe other end presses on one of the clamping edges of the housing forconnecting the housing with the connecting block or the explosion panelwith the holder.

The use of two diverging clip strips means that the resultant of the twopressures acting obliquely on the clamping edges is vertical, so thatthe whole is in equilibrium and the explosion panel is blown awayvertically, so that furthermore all friction between the explosion paneland the frame fastened around the safety opening is avoided. Anotheradvantage is that each individual clamping device is sheltered in asealed housing, so that no problems with the accumulation of dirt needbe feared and that the replacement of the clamping means is easy tocarry out. Another major advantage is that this clamping device permitsthe use of a common and inexpensive composite panel such as used inbuilding structures and which are less subject to deformation thanexplosion panels in stainless steel. Moreover such panels have extremelygood thermal insulating characteristics and in many cases prevent theformation of condensation on the panel.

By way of example a more detailed description of a preferred but in noway limited embodiment of the clamping device pursuant to the inventionfollows below. This description refers to the attached drawings where:

FIG. 1 shows a front elevation of the clamping device and the explosionpanel mounted on the holder;

FIG. 2 shows a plan view of the same;

FIG. 3 shows an enlarged longitudinal section through one of theelements of the clamping device along line III--III in FIG. 2;

FIG. 4 shows the same longitudinal section as that in FIG. 3 but wherethe explosion panel is released from the holder;

FIG. 5 shows a cross section of one element of the clamping device alongline V--V in FIG. 3.

In these figures can be seen the holder 1 in which any sort of powder,gas or vapour is present and which is provided with a safety opening 2which must be closed. Around this opening a frame 3 is mounted on theholder in any way whatsoever. On this frame several upright connectingblocks 4 are mounted at a distance from one another by means of screws5. Each connecting block 4 has as threaded opening 6 in which the heightof a screw 7 can be set. This screw passes through an opening which isprovided in a bearing element 8 the cross section of which is aninverted L and on which the head of screw 7, which serves to preset thetension, can exert pressure. One end of each of the two divergingstraight clip strips 9 which lie in a plane which runs angled to thelongitudinal direction of frame 3 engages in this bearing element 8. Theother end of each clip strip 9 engages in a clamping edge 10 provided onthe lower edge of each end surface of a housing 11 the bottom surface ofwhich is open and which fits over the connecting block 4 and closesagainst its base, so that the whole is adequately protected againstdeposits of dirt. Each housing 11 is attached by one side surface bymeans of screws 12 to the side of a stiff explosion panel 13 whichconsists by preference of a composite panel such as used in buildingstructures. Each housing 11 is provided with a cover 14 which enablesthe clip strips 9 to be easily installed in the housing and the screw 7and the supporting element 8 to be adjusted in height so that presettension of the clip strips 9 and consequently the clamping force betweenthe housing 11 and the connecting block is adjustable. The pressure atwhich the explosion panel will be blown away is, determined by thebuckling strength of the clip strips and thus largely depends on thematerial selected and the dimensions of the clip strips.

When an explosion occurs in the holder 1, the generated pressure exertsupward pressure on the explosion panel 13, which pressure is transferredby the housings 11 with clamping edges 10 to the clip strips 9. When thebuckling strength of the clip strips 9 is exceeded, these strips buckle,so that the explosion panel 13 with the housings 11 slides verticallyover the connecting blocks 4 and is blown away from the safety opening 2of the holder 1. After a mild explosion the explosion panel is usuallynot damaged and it is sufficient to replace the clip strips and/or theconnecting blocks 4 and the housings in order to return the clampingdevice to service.

It goes without saying that the form, the number and the dimensions ofthe components described above may differ and that some of thesecomponents might be replaced by others which are intended for the samepurpose. Thus instead of straight clip strips use could be made ofpre-formed single or multiple clip strips.

I claim:
 1. A clamping device for stiff explosion panels for closing offa safety opening in a holder filled with powder, gas or vapor, where aframe is fastened around the safety opening and several inclined clipstrips are provided between the frame and the sides of the explosionpanel for pressing the explosion panel onto the frame, characterized bythe fact that: the clamping device comprises plural upright connectingblocks, for each connecting block a housing which fits over theassociated connecting block to cover the connecting block, in eachhousing two clamping edges lying opposite one another, said connectingblocks and housings being spaced apart, one of each of said connectingblocks and associated housing being fastened to the perimeter of theexplosion panel and the other to the perimeter of the frame, and in eachhousing at least two diverging clips strips, one end of each strip beingsupported by the connecting block and the other end pressing on one ofthe clamping edges of the housing in order to connect the housing to theconnecting block, and, in turn, the explosion panel to the holder. 2.Clamping device according to claim 1, characterized by the fact that thehousings are fastened with their rear surfaces to the sides of theexplosion panel, whereby the diverging clip strips run transverse to theback surface of each housing.
 3. Clamping device according to claim 1,characterized by the fact that the lower edge of each end surface of thehousing is finished in an inward turning clamping edge on which one endof a clip strip rests.
 4. Clamping device according to claim 1,characterized by the fact that a tension adjuster is provided betweeneach connecting block and the clip strips for presetting the tension ofthe clip strips.
 5. Clamping device according to claim 4, characterizedby the fact that the tension adjuster consists of a verticallyadjustable screw in the connecting block and a bearing element on whichthe head of the screw exerts a pressure and in which one of the ends ofeach clip strip rests.
 6. Clamping device according to claim 1,characterized by the fact that the explosion panel consists of acomposite panel structure.